This invention is related generally to inflatable vehicle protective devices and, more particularly, to an expansible bolster element disposed along the flooring surface of a vehicle and deployable upwardly towards the feet of the vehicle occupant upon the occurrence of an activating collision event.
Inflatable bolsters have been developed to enhance vehicle occupant protection in the event of sudden vehicle deceleration. In particular, such devices have been developed in the form of knee bolsters to increase the duration of deceleration of occupants"" femurs and to control upper torso kinematics during a frontal impact event. Representative knee bolster systems are illustrated and described in U.S. Pat. Nos. 6,213,497 and 6,203,057 to Spencer et al. the teachings of which are each incorporated by reference as is fully set forth herein. In such systems, the bolster impact surface is moved from a stored position to an extended position to intercept occupants"" knees early in the impact event. This allows the knees more time to decelerate to the final velocity of the vehicle. The initial positioning of the bolster impact surface in a retracted stored position allows styling flexibility and enhances leg room prior to deployment.
While deployable knee bolsters are believed to provide substantial protection to the knees and femur of a vehicle occupant, such systems do not substantially address energy transfer between the occupants"" feet and the underlying vehicle flooring. Impact studies have recently shown that during a sudden deceleration interaction between an occupant""s feet and the flooring surface of the vehicle may lead to injury. Such injury may be particularly likely to occur during the act of braking as the operator of the vehicle attempts to respond in a rapid manner to a perceived impending collision event. The possibility of injury may be enhanced as the foot pivots during interaction with the braking pedal. Furthermore, if the foot is not centered in the middle of the brake pedal, the possibility exists that the foot may turn to one side thereby further promoting the potential for injury. Of course, in the case of a vehicle incorporating a manual transmission, such issues are also encountered with respect to operation of the clutch pedal. Moreover, non-operating vehicle passengers may be subjected to similar types of energy transfer which may lead to injury during a deceleration event such as when the foot is not positioned squarely on the flooring surface.
Common injuries seen in the lower extremities of occupants following collision events include heel injuries, ankle injuries, and injuries to the lower tibia. Such injuries are generally the result of contact between the heel and the toe pan region of the flooring surface. The use of static padding elements to support the foot under the heel area has been contemplated. However, due to the limited space availability below the operating pedals, padding of sufficient thickness to provide substantial benefit may be difficult to incorporate. Moreover, if padding of excessive thickness is used, the feet may be forced into localized compressed pockets surrounded by a raised surface of uncompressed padding. Such localized indentation may be undesirable in the event of a secondary impact such as a side collision due to the fact that the feet are unduly constrained.
This invention provides advantages and alternatives over the prior art by providing a highly efficient energy absorption device to support the foot and heel during a rapid deceleration event. The device also aids in preventing an operator""s foot from slipping off the brake and/or clutch pedals if contact between the foot and the pedal is off center when in the braking mode. In addition, the device incorporates a shallow profile configuration which occupies only a minor degree of space beneath the feet of the occupant and which may be hidden in a substantially undetectable manner beneath the carpeting on the vehicle floor.
These advantages are accomplished in a potentially preferred form of the invention by providing a hollow expansible enclosure adapted for storage at the intersection of the toepan and floorpan regions of the vehicle floor. The hollow enclosure is expansible away from the underlying flooring support surface and generally towards the foot of the occupant to be protected so as to engage the foot at an early stage of the deceleration event and to thereafter provide prolonged supporting contact between the hollow enclosure and the foot. The hollow enclosure is preferably formed of a substantially rigid material such as plastic, polycarbonate, or the like so as to provide a substantially non-cavity forming expanded surface for interaction with the foot of the occupant to be protected.
Preferably, the hollow enclosure is of a generally profiled geometry so as to mate with the contour of the interface between the toepan and the floorpan regions of the underlying flooring support surface. The expanded depth dimension of the hollow enclosure may be either uniform throughout the structure or may be enhanced in a region substantially in opposing relation to the heel of the occupant to be protected so as to provide added energy absorption at that location. The hollow enclosure may also have an enhanced expanded profile extending in a direction laterally of the foot of the occupant to be protected so as to offset the effects of lateral flexion in the event that the foot is misplaced or slips off of the pedal during the deceleration event.
Preferably, expansion of the hollow enclosure is carried out by the collapsible deformation of accordion style rib elements normally extending in raised and lowered relief away from the underside of the enclosure and towards the face portion thereby causing the face to be projected towards the foot of the occupant to be protected. The materials forming the underside and the face portion may be either similar or dissimilar in character. If desired, the hollow enclosure may be formed as a single piece construction by means of highly efficient injection or blow molding techniques.